This invention relates in general to coke ovens and in particular to a new and useful immersion-type seal for a coke oven standpipe, which includes a seal member or frame which has an annular lower peripheral spherical surface with seats on a ring which is placed on a rim of the standpipe of the coke oven and a lid which cooperates with the seal frame in closing the top of the coke oven standpipe.
An immersion-type seal is known from German utility model application No. 7807265. In gas conduction lines, water seals have proved satisfactory at differential pressures of up to some hundred millimeters of water column. They have recently been successfully tested also in connection with standpipe covers, so that they are now used for this purpose at a growing rate in new coke oven plants. In existing plants where the usual standpipe lids are provided with a dry metallic seal, there is also a tendency to re-equip the standpipes with an immersion-type seal. That is, experience has shown that with conventional dry metallic seals, after a longer period of service and, particularly, if the sealing faces are insufficiently cleaned from crude tar deposits, strong coal gas emissions frequently occur causing considerable pollution of the environment.
Both in new plants and in re-equipped ones, the use of immersion-type seals for standpipe lids requires the necessary water level in the seal during the entire time period of operating the coke oven chamber, and also at all locations of the water trough. It is known to size the water trough sufficiently to ensure that a single filling with water will secure the seal throughout the entire coking time of an oven, in spite of the intense evaporation caused by the high temperatures, so that one filling at the start of the cycle will do. Another possibility is to provide a trough with an inlet and outlet and to circulate the water continuously. This is advantageous insofar as, according to experience, the temperature of the water remains uniformly at a low level, less water evaporates, and with calcareous water, boiler-scale deposits are eliminated to a large extent.
What is particularly important in any case of using immersion-type seals for standpipe lids is to ensure that the water trough constantly remains in a horizontal position. This is a problem with standpipes on coke ovens, which, at the present state of the art, are up to 6 meters high and are supported on the refractory wall structure of the coke ovens which may become displaced by the unequal dilation during the heating-up period and cause an inclined position of the standpipes. Primarily in existing plants, it would be very expensive to rectify the position of inclined standpipes or to provide individually adjusted intermediate pieces for each of the standpipes. The same, however, goes for the initial period of operation and corrections during the following years in new plants.